View Single Post
Old 07-30-2010, 10:47 PM   #9 (permalink)
Wiki Writer
Join Date: Jul 2010
Location: Melbourne, Australia
Posts: 236

bugler - '91 Mazda 626
90 day: 35.89 mpg (US)
Thanks: 15
Thanked 25 Times in 22 Posts
Zerohour, good luck, I am in the same position as you so i look forward to seeing what works for you.
Maybe some of my mods will give you some ideas too, so here they are.
I am driving a 91 mazda 626 with 2.2 L engine and Auto transmission.
EPA MPG is 22. I have currently been able to get 27.7 but i still have a lot of mods to go yet. The mods i have done so far are nice low hanging fruit, very easy to do. if i knew what i was doing at the start these would have only taken a day all up ( I messed around for 3 days trying to move to a manual steering rack then half way through i realised i should have just disconnected the hydraulic lines because the gearing is so similar between the manual and automatic racks)

current mods
- both side mirrors delete (I dont use them anyway, i do head checks)
- single windscreen whiper delete (passenger side)
- wheel mud guards delete
- flat wheel hub covers. (Small circle of flat plastic screwed onto the well hub
- removed air con which removes a drive belt
- some weight removed, all air con parts, some carpets, power steering most asthetic things in my boot
- Changed power steering to manual steering (disconnected hydrolic lines which makes turning harder but still drivable)
- reduced idle and placed switch in cabin to put ECU into diagnostic mode which stops it from compensating for low idle. Idle is down to 600 rpm from 800, Only stalled once and some threads here suggest low rpm may reduce lubrication but i figure if my engine dies or transmission dies i will just buy a new car that is already efficient then ill make it better.
- Wheel PSI increase, easy to do, little risk, slighty harder to drive but barely noticable

Driving habbits
- P&G when possible, I thought this couldn't be done in an auto but after reading some posts here realised i can. So when at speed i go into neutral (with low idle) then let it coast down. When going back into drive i rev the engine to match RPM and pop it back in, If the revs are matched little wear on transmission and no jolt from changing into drive.

I recommend getting a scanguage or some diagnostic gadget which tells you how much fuel you are using if you havn't already. I made one up myself so cant recommend a good one. It does let you work out what mods are good for you and changes your driving habbits. All cars are different so some real time feedback of what your mods or driving habbits are doing is very valuable.

The mods that worked the best for me were
- Mirror delete, mud flap delete and car wheel covers
- idle reduction as i am lights a lot in my standard commute

as for planned mods they are below
- belly pan
- front grill cover
- radio antenna delete
- cover up gaps for aerodynamics
- cold idle speed reduction
- reduction in idle when shifting to neutral in the cold
- automatic transmission gear manual control
- Torque converter control
- Improved wheel well aerodynamics

will have to see how they go, im hoping to 39 mpg or better but any improvement will be good

Im currently concentrating on reducing the idle at cold because my trips to work are short (10 minutes) and the high cold idle far outweighs any aero or driving habbit improvements.

so good luck, let us know what works well for you
  Reply With Quote